I'm also wondering if this would work with http://jitsi.org ?
Kenneth, I see no reason, why this should be impossible. In order to use LTI-services, you have to (a) install the OpenACS LTI package [1] on a recent version of OpenACS (oacs-5-10), (b) install/configure/access the services you want to call via LTI (e.g. install BigBlueButton and configure it), (c) add the necessary parameter to the LTI configuration (e.g. in the configuration file, see [1]), and (d) decide, where in your OpenACS installation you want to launch the service (e.g. from a wiki page).
[1] https://openacs.org/xowiki/accessing-lti-services